Among both athletes and non-athletes, the popularity of weight training exercise has substantially increased in the past ten years. In addition to the use of traditional "free weights", i.e., plate-loaded barbells or dumbbells, weight training exercises are also performed with a number of specialized exercise machines that work a particular muscle group through a prescribed motion or exercise maneuver. Generally, for most exercise maneuvers that may be performed either on a machine or with free weights, exercise machines tend to be safer. Moreover, from a practical standpoint, certain exercise maneuvers are simply more efficient and beneficial when performed on an exercise machine, particularly when the major purpose for performing weight training is to rehabilitate an injured limb.
In addition to rehabilitation, another purpose of weight training is the prevention of injuries. By building up the muscles associated with a particular movement and the joints involved with that movement, the likelihood of injury can be reduced.
One relatively common injury among baseball pitchers is that of damage to the rotary cuff. An injury to this part of the shoulder can ruin a career. Among athletes who participate in sports other than baseball, either professionally or simply for enjoyment, damage to the rotator cuff can impair even simple movements of the arm, or at least make performance of these movements extremely painful. In short, for athletes participating at all levels of competition, there exists a genuine need to strengthen muscles associated with the shoulder to reduce the occurrence of painful damage to, or physical impairment of the rotator cuff.
While this need is rather simply stated, it is not so easily met. The shoulder joint is a ball and socket type joint. To effectively exercise the muscles associated with the rotary cuff joint, an exerciser's arm must be extended outwardly from the torso, in a direction generally perpendicular to the torso. From this position, forward movement of the lower arm and hand produces "internal rotation" of the upper arm in its socket, while rearward movement produces "external rotation" of the upper arm in its socket.
It is difficult to isolate the rotary cuff joint when performing either of these two rotary movements with a dumbbell or a barbell. First of all, if the elbow is not supported, the force of any weight grasped by the hand will be felt by the entire arm and will distort the muscular effect to such an extent that the desired benefits to the shoulder joint will not be achieved. If the elbow is supported, it becomes necessary to use the other arm to hand off the desired weight to the exercising arm.
While this physical inconvenience may be tolerable when exercising one arm at a time, it presents problems for an exerciser wishing to exercise both arms simultaneously. The exerciser must grasp the weights with both arms and then move to the desired exercise position. After completing the exercise, the reverse movement is required. Because many weight training exercises are performed to the point of fatigue, or until failure occurs, movement of the arms and hand-held weights out of an elbow supported rotary cuff exercise position may present a danger of dropping the weights. In short, the inherent dangers associated with moving two separate weights into and out of a desired rotary cuff exercise position may outweigh the benefits derived from performance of the exercise.
On the other hand, it seems that the relatively high cost of exercise machines has effectively diminished the incentive to design and develop an exercise machine dedicated solely to exercising the rotary cuff joint through both the internal and external rotation. As a result, although many exercise machines do provide some muscular benefit for the shoulder, none are designed specifically for the purpose of isolating and exercising the shoulder muscles associated with the rotary cuff joint.
It is an object of this invention to provide an exercise machine that isolates the shoulder muscles during a rotary cuff exercise maneuver to maximize muscular benefit to the rotary cuff joint.
It is another object of this invention to provide a rotary cuff exercise machine that an athlete may use to reduce susceptibility to rotary cuff injury and/or rehabilitate a rotary cuff injury that has already occurred.